A frigid day in January 2006. The police stumble upon a horrifying scene in the Swedish town of Hudiksvall: 18 people have been brutally murdered overnight. Authorities suspect a deranged killer is responsible. However, when Judge Birgitta Roslin hears the news, she quickly realizes that her grandparents, August and Britta Andrén, are among the victims. Disturbingly, she finds that nearly all the murdered individuals are somehow connected to her. Understanding that the police are on the wrong track, Birgitta takes matters into her own hands. Her investigation leads her to China, where she uncovers the sinister machinations of the ruling elite.